From: Dave Jones <davej@redhat.com>

We seem to be hitting this assertion failure too often for it to be
hardware bugs.

Cc: Hugh Dickins <hugh@veritas.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 mm/rmap.c |    7 +++++++
 1 files changed, 7 insertions(+)

diff -puN mm/rmap.c~rmap-additional-diagnostics-in-page_remove_rmap mm/rmap.c
--- 25/mm/rmap.c~rmap-additional-diagnostics-in-page_remove_rmap	Wed Jan  4 16:41:36 2006
+++ 25-akpm/mm/rmap.c	Wed Jan  4 16:41:36 2006
@@ -514,6 +514,13 @@ void page_add_file_rmap(struct page *pag
 void page_remove_rmap(struct page *page)
 {
 	if (atomic_add_negative(-1, &page->_mapcount)) {
+		if (page_mapcount(page) < 0) {
+			printk (KERN_EMERG "Eeek! page_mapcount(page) went negative! (%d)\n", page_mapcount(page));
+			printk (KERN_EMERG "  page->flags = %lx\n", page->flags);
+			printk (KERN_EMERG "  page->count = %x\n", page_count(page));
+			printk (KERN_EMERG "  page->mapping = %p\n", page->mapping);
+		}
+
 		BUG_ON(page_mapcount(page) < 0);
 		/*
 		 * It would be tidy to reset the PageAnon mapping here,
_